This research program is directed toward the continued development and application of new ultrasound imaging procedures for cardiovascular diagnosis. The research objectives include both the technical development of new B-mode imaging instruments and the clinical development of new diagnostic applications. Technical development will be directed toward the completion of an extremely flexible new digitally controlled phased array research imaging system; the design, fabrication, and testing of improved ultrasound transducer arrays for such imaging systems; and the evaluation and optimization of a new on-line multi-dimensional real-time image processing system that has been designed specifically for B-mode ultrasonography. Clinical development will be directed toward the evaluation of the diagnostic usefulness of the images obtained and toward expanding the breadth of applicability of the diagnostic use of ultrasound. Specifically, in addition to adult cardiac diagnosis, areas such as the peripheral vasculature, abdominal vasculature, cerebrovasculature, and pediatric hearts will be studied.